const grpc = require('@grpc/grpc-js')
const message_proto = require('./proto')
const const_module = require('./const')
const { v4: uuidv4 } = require('uuid')
const emailModule = require('./email')
const redis_module = require('./redis')

async function GetVerifyCode(call, callback) {
    console.log("email is ", call.request.email)
    try{
        // 获取验证码之前可以先查询redis，如果没查到就生成uid并且写入redis
        // (code_前缀 + 邮箱地址将其作为一个key) + uuid
        let query_res = await redis_module.GetRedis(const_module.code_prefix + call.request.email); 
        console.log("query_res is ", query_res)
        if(query_res == null){

        }

        let uniqueId = query_res;
        // redis中不存在验证码，则生成验证码
        if(query_res == null){
            uniqueId = uuidv4();
            if (uniqueId.length > 4) {
                uniqueId = uniqueId.substring(0, 4);
            } 
            let bres = await redis_module.SetRedisExpire(const_module.code_prefix + call.request.email, uniqueId,600)
            if(!bres){
                callback(null, { email:  call.request.email,
                    error:const_module.Errors.RedisErr
                });
                return;
            }
        }

        console.log("uniqueId is ", uniqueId)
        let text_str =  '您的验证码为'+ uniqueId +'请三分钟内完成注册'
        //发送邮件
        let mailOptions = {
            from: '15595542046@163.com',
            to: call.request.email,
            subject: '验证码',
            text: text_str,
        };
        let send_res = await emailModule.SendMail(mailOptions);
        console.log("send res is ", send_res)
        callback(null, { email:  call.request.email,
            error:const_module.Errors.Success
        }); 
    } catch(error) {
        console.log("catch error is ", error)
        callback(null, { email:  call.request.email,
            error:const_module.Errors.Exception
        }); 
    }
}

function main() {
    var server = new grpc.Server()
    server.addService(message_proto.VerifyService.service, { GetVerifyCode: GetVerifyCode })
    server.bindAsync('0.0.0.0:50051', grpc.ServerCredentials.createInsecure(), () => {
        server.start()
        console.log('grpc server started')        
    })
}

main()